1. Field of the Invention
The present invention relates to a data storage subsystem also known as an auxiliary storage manager. The auxiliary storage manager is responsible for moving frames from central storage to auxiliary storage (AUX). The auxiliary storage is usually a file on a direct access storage devices (DASD) or hard disk.
2. Description of the Related Art
One example of implementation of such a subsystem is in the IBM® operating system z/OS®. The IBM® operating system z/OS® is a virtual storage system which comprises mapping virtual storage pages to frames in central storage or slots in auxiliary storage. A virtual storage system, such as the IBM® operating system z/OS®, only loads those portions of a program that are needed for the momentary operation of the program into central storage. The inactive pieces of the program, however, are kept in auxiliary storage. An auxiliary storage manager is responsible for moving storage pages or data blocks from the central storage to the auxiliary storage when not currently needed. Another component of the z/OS operating system is the workload manager. It controls access to system resources for the work executing on z/OS based on administrator-defined goals.
New storage technologies provide non-volatile storage devices with different access speeds. For example new devices such as Flash memories are faster than conventional slower DASD (direct access storage devices) or hard disk drives. Therefore the need for a suitable workload allocation arises.
Different state of the art documents are concerned with storage or memory allocation. Document US 2009/0019097 describes a system and method for memory allocation management. Memory allocation requests comprise parameters for indicating requirements including a priority, a mandatory status etc. Each of a plurality of memories, such as scratch memory, persistent memory, etc., is characterized by operating speed, capacity and suitability of application types. Memory allocations are optimized by examining the parameters and a memory map is generated.
Another state of the art document, U.S. Pat. No. 7,062,628, describes a method and apparatus for storage pooling and provisioning for journal based storage and recovery. A set of interconnected storage systems supporting different types of storage devices and different performance attributes are intelligently applied to process types, such as journal entries. The processes are ranked according to a predetermined priority ranking. The highest priority process is matched with available devices from storage pools that rank highest in the processes performance priority. The storage pools are ranked according to capacity, reliability, and access rate.
Document U.S. Pat. No. 6,760,910 describes a workload distribution management method to enhance shared resource access in a multi-system environment and to meet a common performance standard. The method comprises dynamically tracking use by a plurality of work classes of a plurality of resources in the multi-system. Each work class comprises at least one work unit. A system resource manager dynamically forms a plurality of sets of the shareable resources and dynamically associates each work class with a set of the shareable resources based on resources currently employed by the at least one work unit.
The problem is that new storage technologies provide non-volatile storage devices with different access speeds, for example, a Flash memory is faster than conventional slower DASD (direct access storage devices) or hard disk drives. To enable fast data processing, the time needed for moving pages from the auxiliary storage back to the central storage should be as short as possible. A complete replacement of the slower auxiliary storage devices with the faster ones may become too expensive. Therefore, an economic way to distribute pages over the storage devices with different access speeds is desired.